Vermiculite paste for sealing pistons



20 when internal combustion engines have besize from the very smallest to the largest that 20 25 the useof oversized pistons. Such reconditioning foliated vermiculite may vary somewhat, but 25 cylinder is that when they are rebored, the hardmineral oil of any suitable grade or quality, but 30 vmmcuu'rs ras'rs roa smmm -rrs'rous. I

Harold s. Brinker and B. Thomas, Denver, Colo., aasignors to Motor Seal Qumration, Denver, 0010., a corporation of Colorado No Drawing. Application October 30, 1933,

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, This invention relates to a method and a prodthe sealing operation, ordinary vermiculi uct for producing gas tight se'alsbetween relawhich is sometimes ferred to as Jeifersitle, is tively moving bodies such as between the piston taken from the mine and cleaned so as toremove and cylinder of an engine or between the piston as much as possible of the'grit and sand that rings and the piston ring groovesin the pistons.- might be present. After the first cleaning, the B ,It is well known that internal combustion envermiculite is ground to a size that will barely gines of the type employed in automobiles rare pass through a half inch mesh screen and is then operated under conditions that produce rapid subjected to a differentialscreening effect wherewear of the piston rings andthe cylinder surfaces by the grit and foreign particles that have been 10 with the result that the seal between the piston reduced to a small size, will be separated from the 10 and the cylinder frequently becomes defective to larger vermiculite particles. After this screening such an extent that the gasesproduced by-the operation, the vermiculite, which is then quite burning of the gaseous mixtures escape from the free from foreign matter, is ground to a fine 1 combustion chamber into the crankcase with a powder and subjected to a screening operation resultant lossof power. In addition to the loss and employing for this purpose a mesh screen 15 of power, leaky piston rings permit oil to be that will limit'the maximum dimension of the pumped into the combustion chamber, thereby inparticles'to those permitted to pass through this creasing the amount of carbon produced and inscreen. The vermiculite that passes through'the creasing the cost of lubricating the engine. A screen will then consist of particles varying in come lealw as above intimated,v it is usually necwill pass through the screen.

essary to remove the pistons and supply them The ned vermiculite is now mixed with with new pistonrings and it isalso frequently nec-' powdere roasted or exfoliated vermiculite and essary to rebore the cylinders which necessitates the proportions. of unexfoliated vermiculite to exof an engine is expensive and is only. temporary preferably the roasted vermiculite comprises because the reconditioned pistons and cylinders about one-third of the mixture, the balance being will soon wear away and become leaky. Another unexfoliated vermiculite. The mixture of roasted objection to the mechanical reconditioning of the and unroasted vermiculite is now mixed with a ened inner surface is removed so as to leave only a very satisfactory paste or mixture has been obthe soft cast iron that then wears away faster tainedby employing steam engine valve oil with than the original surface. which may be mixed a small percentage of pene- We have discovered that if a paste is formed .trating oil'.. The oil and the mixture of powdered 5 from a mixture of unexfoliated and exfoliated vermiculite are thoroughly stirred so as to form vermiculiteand oil and this paste introduced into a homogeneous paste which can be placed in colcylinders of an internal combustion engine which lapsible tubes in which the paste is sold and from is then permitted to idle for a few minutes, the which it is di paste will flow into the space between the cylinder When an engine is to be treated by the process 0 wall and the piston and be forced downwardly by defined in this application, the spark plugs are 40 the pressure so as to pass into the space between removed while the engine isstill hot and a quanthe sides of the piston rings and the sides of the tity of the paste is introduced into each cylinder. piston ring grooves and that if the parts are then The spark plugs are now replaced, after which heated .to a temperatm'e higher than that rethe engine is-started and permitted to idle'for 5 quired for exfoliation of the vermiculite, the un- -a few minutes, 'flve minutes has been found as exfoliated particles of vermiculite that have been suilicient for this purpose. g the idling. carried into the cracks and spaces through which of the engine the pistons and the cylinder walls gases leaked will expand and form an oil and gas are kept hot, but at a temperature below that tight seal. 1 necessary to exfoliate the vermiculite; the heat, Owingtothe'lubricating properties of roasted or however, is sufficient tomake the oil flow freely exfoliated vermiculite, the surfaces separated by and this carries the vermiculite to the sidesof the a layer of this'material will move relative toeach pistons where the mixture flows downwardly beother quite freely as the vermiculite acts as an tween the piston and the cylinder walls and into effective lubricant; Y the space between the piston rings and the sides V In order to prepare the paste which isused in'- -of the piston ring grooves. some of the paste 3 will flow through the space between the inside of of sealing herein described makes it possible to the piston ring and the bottom of the groove cure leaky engines very quickly and very cheapan automobile or other internal combustion envolatilizes and leaves the solid material in place. 10

' It is well known that vermiculite has the propfine powderthat penetrates into places where the city of expanding to many times its original size 'unexfoliated vermiculite'will not pass due tothe l when heated above a certain temperature and expanding action of the heat. since vermiculite is formed from a large number Particular attention is directed to the fact that of thin layers w ich b come Separat by heatthe paste contains a large proportion of unng, the result of the application of heat is reroasted vermiculite particles. It is well underespecially between the sides of the piston rin s changed by the action of the heat and after it and the Sides the Piston g grooves. Y has been heated and, exfoliated, it becomes a luwhen the engine to be e d is an in e a bricant. The paste should have sufficient thickcomhllstien engine, the necessary h a ca eas y mess to prevent the solid particles from settling. be obtained, but if the process is to be applied to This application is a continuation, in part, of apa steam engine, the use of ordina y satu a ed plication, Serial No. 673,566, filed May 29, 1933.- Slieam l Deli raise h temperature Suflicielitly Having described the invention what is claimed .to produce exfoliation and therefore it is neceshis n w is; a y o mp y hi y super-heated steam until 1,.A paste for use in forming seals between the D is c fll eh y heated to exfoliate relativelymovable surfaces of heated bodies conthe vermiculite. s

Y a ng e a ticl s of v c lite o di lite particles in the proportion of one part of the ferent rit s appa nt hat w e th spa e former to three parts of the latter mixed with a to be- Sealed is v ry'small, only the Smaller D suflicient. quantity of oil to form a paste.

ticles enter, but where the space is large, 2 Apaste for u'sei From experience it has been found that when of the latter, mixed with a suflicient quantity of ehgines that are leaky and which are worn to il to form a, paste,

slleh 8h extentv t D a takes plac 3. A paste foruse in forming seals between relx operation; re treated 85 above described atively movable surfaces of heated bodies con theope lng o gh wh ch the gas and oil Pass sisting of a mixture of exfoliated and unexfolie y t ly al d and enough of the' ated vermiculite particles mixed with a lubricant.

prevent piston slap; I HAROLD s. BRINKER. It evident fromthe above that the method WILLIAM B. THOMAS,

ferred to as exfoliation. When the unroasted stood that unexfoliated vermiculite-is not pos- 20 r with the resllll; the! e y ellective a s d, I consideration is "that its properties are soon :25

11 forming seals between rel-. 4p 

